1. Field of the Invention
The present invention relates to a recording apparatus, and more particularly to discharge pattern generation.
2. Description of the Related Art
An ink jet recording apparatus of a serial type forms an image by moving a carriage having a recording head mounted thereon in a main scanning direction that is different from a paper feeding direction, and discharging inks from nozzles of the recording head.
Such recording apparatus typically includes a printing buffer (recording buffer) for holding recording data to be transferred to the recording head. As to a memory capacity of the printing buffer, an amount sufficient for holding all data to be recorded in at least one main scanning direction is typically provided (printing buffer of 1 band).
For example, when recording is carried out in an 8-inch width at resolution of 600 dpi in a main scanning direction and a recording head has 128 nozzles arranged at 600 dpi in a subscanning direction, a printing buffer necessary for one main scanning may require a memory capacity of 76800 bytes per color.
In order to realize high quality image, a multidroplet method is available. In the multidroplet method, plural amounts of each color ink are discharged while one kind of a discharge amount is conventionally permitted per color. Alternatively, a multicoloring method is also available which adds photocyan (PC) and photomagenta (PM) to four basic colors of cyan (C), magenta (M), yellow (Y) and black (K) to improve a gray scale of a photo-image. Accordingly, a memory capacity necessary for the recording apparatus tends to increase.
Moreover, in order to realize a high printing speed, attempts have continuously been made to reduce the number of scanning times necessary for printing one page by increasing the number of nozzles of each color. This also tends to increase a memory capacity of the printing buffer.
An increase in printing buffer size leads to a cost increase of a printer. However, in association with an increase in number of host apparatus (host computers) put into a market and a reduction in its price, there has been a trend in price reduction of ink jet recording apparatus in the market. Especially, a price reduction has been conspicuous in a low-end ink jet recording apparatus. To realize the price reduction, a memory size of an ink jet printer is reduced so that the price can be lowered. For example, there is a method that reduces a printing buffer size such that it is smaller than an amount of data associated with one main scanning direction.
For example, there has been a proposal to reduce printing buffer size by controlling main scanning to start before data input of one main scanning amount is completed in a buffer (JP A 11-259248). There has also been a proposal to carry out a recovery control when data transfer from a host apparatus to a recording apparatus is not in time because of an increase in processing load or the like caused by multitask processing of a CPU in the host apparatus (JP A 2003-305903).
An ink jet printer typically incorporates a function of printing a nozzle check pattern to enable a user to check a status of the nozzles arranged in the recording head.
In the case of a printer capable of securing a printing buffer of one band, a process is started when a predetermined command is sent from the host apparatus or nozzle check pattern printing is confirmed by a predetermined key operation. In other words, a paper feeding operation is executed, a bit pattern of nozzle check patterns necessary for one scanning is rasterized on the printing buffer, and carriage scanning is started.
When the recording of one scanning is finished, paper feeding is carried out at a predetermined conveying rate. After an end of the paper feeding, a next bit pattern necessary for one scanning is rasterized on the printing buffer of one band, and carriage scanning and paper feeding are carried out as described above. Pattern rasterization, carriage scanning, and paper feeding of a bit pattern necessary for one scanning are repeated by a predetermined number of times in the printing buffer and, after recording of a last nozzle check pattern is finished, a sheet is discharged to finish the nozzle check pattern printing mode.
In a normal recording operation (recording mode), data is stored in the printing buffer based on received data sent from the host apparatus. Recording is carried out using the data stored in the printing buffer. On the other hand, in the nozzle check pattern printing operation (mode), recording data may be generated in the printing buffer using a pattern stored in a ROM based on a control code of the ROM disposed in the recording apparatus. Then, a recording operation is carried out using this recording data. Accordingly, the generation process of recording data is much different between the two modes.
In a case of nozzle check pattern printing in a printer incapable of securing a printing buffer of one band, recording is carried out by transmitting a nozzle check pattern from the host apparatus to the printer. Specifically, the nozzle check pattern is incorporated as a print file into a printer driver beforehand and, when printing of the nozzle check pattern is selected from a maintenance tab of the printer driver, the print file is transferred to the printer (JP A 2004-102445).
However, the above technology is based definitely on a premise that the printer driver is successfully installed in the host apparatus, and the host apparatus and the printer are connected to each other.
Because of such a premise, a user of the printer is required to set the host apparatus to be in a power-ON status to print the nozzle check pattern. Then, the user is required to check installation of the printer driver. This is inconvenient for the user, imposing time and labor burden on the user. If the user cannot correctly use the printer driver, even when the host apparatus is operating, the user may not be able to print the nozzle check pattern.